title: Fast and accurate nonenzymatic copying of an RNA-like synthetic genetic polymer.
abstract: Recent advances suggest that it may be possible to construct simple artificial cells from two subsystems: a self-replicating cell membrane and a self-replicating genetic polymer. Although multiple pathways for the growth and division of model protocell membranes have been characterized, no self-replicating genetic material is yet available. Nonenzymatic template-directed synthesis of RNA with activated ribonucleotide monomers has led to the copying of short RNA templates; however, these reactions are generally slow (taking days to weeks) and highly error prone. N3'-P5'-linked phosphoramidate DNA (3'-NP-DNA) is similar to RNA in its overall duplex structure, and is attractive as an alternative to RNA because the high reactivity of its corresponding monomers allows rapid and efficient copying of all four nucleobases on homopolymeric RNA and DNA templates. Here we show that both homopolymeric and mixed-sequence 3'-NP-DNA templates can be copied into complementary 3'-NP-DNA sequences. G:T and A:C wobble pairing leads to a high error rate, but the modified nucleoside 2-thiothymidine suppresses wobble pairing. We show that the 2-thiothymidine modification increases both polymerization rate and fidelity in the copying of a 3'-NP-DNA template into a complementary strand of 3'-NP-DNA. Our results suggest that 3'-NP-DNA has the potential to serve as the genetic material of artificial biological systems.
authors.affiliation: Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114.
authors.forename: Shenglong
authors.initials: S
authors.lastname: Zhang
authors.forename: J Craig
authors.initials: JC
authors.lastname: Blain
authors.forename: Daria
authors.initials: D
authors.lastname: Zielinska
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Gryaznov
authors.forename: Jack W
authors.initials: JW
authors.lastname: Szostak
mesh_terms: D000577:Amides / Q000737:chemistry*; D058045:Artificial Cells / Q000378:metabolism*; D002853:Chromatography, Liquid; D004247:DNA / Q000737:chemistry*; D005818:Genetic Engineering / Q000379:methods*; D013058:Mass Spectrometry; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D010756:Phosphoric Acids / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D017422:Sequence Analysis, DNA
chemical_list: D000577:Amides; D010756:Phosphoric Acids; D011108:Polymers; D004247:DNA; C011067:phosphoramidic acid
keywords: artificial genetic systems; mismatch; nonenzymatic primer extension; nucleotide modifications; origin of life